Tiki Barber knows Mark Sanchez can play despite a strained posterior cruciate ligament. How does Barber know this? He played virtually his entire 10-year career without a PCL in his right knee.

How’s that? Barber in the fifth game of his rookie year (1997) with the Giants completely tore his PCL against the Saints, causing him to miss the next four games.

“It forced me to change my game and how I ran,” Barber recently told The Post. “It’s not a fun injury. The reason it was bad is you have a lot of laxity in your joint all of a sudden, so if you don’t strengthen your quads and your hamstring and your calf muscle you’re in danger of tearing cartilage, which really puts you on the shelf.”

Sanchez is dealing with a strain, not a complete tear, but don’t assume the strain is preferable in the short run.

“It’s almost worse, because it’s painful that way,” Barber said. “It’s better if you tear it because you tear the nerve, it might preclude some function, but you don’t have to worry about it aching for how many weeks there are left.”

Dealing with the condition was a constant battle.

“I got stronger, smart with my body, learned how to take care of myself,” Barber said. “You got to realize, you don’t want to call yourself a machine but that’s essentially what we are and all machines have their weak points.

“You have to compensate in other ways, and I was able to do that over nine years and be pretty successful.”

Sanchez will have to adjust as he strengthens his right knee.

“This may be good for them because I know they don’t like him being as mobile and as aggressive as he has been,” Barber said.

“It’s a different problem for a quarterback than it is for a running back, who is always moving forward and cutting. A quarterback historically should be in the pocket, rolling out a little bit. It might not be as detrimental to him as it might be to some other skill positions.”